DESCRIPTION (Verbatim from the Applicant's Abstract): The importance of positron emission tomography (PET) in small animal research has been highly recognized. In the last few years an extraordinary emphasis has been placed on the design and use of PET cameras for small animal studies such as the use of high resolution PET to aid in the development of human gene therapies by imaging transgenic animals such as mice. Although, this imaging technique has an extraordinary potential for both clinical and basic biomedical science application, its full realization is severely hampered by the expense, complexity and physical limitation of crystal detectors widely used in today's cameras. This project will markedly improve sensitivity and spatial resolution of PET while maintaining practical costs by applying a novel lead wall straw (LWS) detector technology conceived by the Principal Investigator. Ph I will establish the smallest practical detector element size and in Ph II a fully functional, small animal imaging system will be constructed to demonstrate proof of principle and to set the stage for human clinical camera development contributing to the markedly improved imaging characteristics including more than ten fold increase in sensitivity and 2-4 fold improvement in spatial resolution with the practical low cost of LWS will ultimately expand the commercial PET camera market and the application of clinical PET. PROPOSED COMMERCIAL APPLICATION: Although widely recognized as the superior nuclear imaging technique, positron emission tomography (PET) has not yet reached commercial potential because of high instrumentation cost and disappointing performance of existing technology. This project will develop a PET technology having both lower cost and markedly improved performance thus widening the commercial market intially for important small animal imaging and later for ultra high resolution human PET.